kenkou no tame ni, maiasa sukosi undousurukoto ni site imasu.

健康のために means for the sake of health or for my health.

• 健康 = health
• の links health to purpose
• ために = for the purpose of, for the sake of

So in this sentence, it gives the reason or goal behind the action:
I do this for my health.

It does not mean because I am healthy. It means in order to stay healthy or improve health.

The の connects the noun 健康 to ため.

You can think of Noun + の + ために as a set pattern meaning:

• for N
• for the sake of N
• for N’s benefit

Examples:

• 家族のために働く = work for one’s family
• 将来のために勉強する = study for the future
• 健康のために運動する = exercise for one’s health

Without の, this phrase would not be grammatical in standard Japanese.

毎朝 means every morning, and 少し means a little.

In this sentence, 少し modifies the exercise action, so the idea is:

• exercise a little every morning

It tells you the degree or amount of the action. In English, we might naturally say:

• I exercise a little every morning
• I do a bit of exercise every morning

So 少し is not a separate object here; it describes how much exercising is done.

The こと turns the verb phrase 運動する (to exercise) into a noun-like idea:
the act of exercising or simply exercising as a concept.

This is needed because the pattern ～ことにしている attaches to こと.

So:

• 運動する = to exercise
• 運動すること = exercising / the act of exercising

Then:

• 運動することにしている = have made it a rule to exercise / make a habit of exercising

You cannot normally say 運動するにしている here. The grammar requires こと.

～ことにしている means I have decided to do... as a regular practice or I make it a rule to...

So 毎朝少し運動することにしています means something like:

• I make it a rule to exercise a little every morning
• I’ve decided to exercise a little every morning
• I try to keep up the habit of exercising a little every morning

The important nuance is that this is not just a one-time decision. It suggests an ongoing personal rule or habit.

Good question.

• ～ことにする = to decide to do something
• ～ことにしている = to have decided and be keeping that decision as a habit or rule

So:

• 毎朝運動することにする
  = I’ll decide to exercise every morning.

• 毎朝運動することにしている
  = I have made it my rule to exercise every morning.

The ている form adds the sense that the decision is in effect now and continues.

In this pattern, にする means to decide on or to make it.

So the structure is:

• Verb-dictionary form + ことにする
• literally: make it that...
• naturally: decide to...

That is why you see に after こと:

• 運動することにする = decide to exercise

Then in your sentence:

• 運動することにしている = have it set as a rule to exercise

So the に is part of the grammar pattern ことにする / ことにしている.

Because しています shows that the decision is ongoing.

Compare:

• 運動することにします
  = I will decide to exercise. / I’m deciding to exercise.

• 運動することにしています
  = I have decided to exercise, and that is my current habit/rule.

In this sentence, the speaker is talking about a continuing routine, so しています is the natural choice.

This ている does not mean the person is literally exercising right now. It means the state of having made that decision continues.

Yes. Japanese often leaves out the subject when it is clear from context.

This sentence naturally implies something like:

• 私は健康のために、毎朝少し運動することにしています。

But 私は is unnecessary unless you want contrast or emphasis.

So the understood subject is usually:

• I
• or possibly someone we are already talking about

In an isolated example like this, English learners should usually interpret it as I.

Yes, that is grammatical, but the nuance is different.

• 毎朝少し運動しています
  = I exercise a little every morning.

This simply states the habit or ongoing action.

• 毎朝少し運動することにしています
  = I make it a rule to exercise a little every morning.

This emphasizes the speaker’s conscious decision or personal policy.

So the original sentence sounds a bit more deliberate, like: I do this on purpose for my health.

Here 運動 means exercise in a general sense.

It can refer to:

• physical activity
• working out
• getting some exercise

So 少し運動する means:

• do a little exercise
• get a bit of exercise

It does not specify exactly what kind of exercise. That could be walking, stretching, jogging, and so on.

Japanese often puts background information first and the main action later.

This sentence is organized like this:

• 健康のために = for my health
• 毎朝 = every morning
• 少し = a little
• 運動することにしています = I make it a rule to exercise

A very literal order would be: For health, every morning a little exercising I have made it a rule to do.

That sounds strange in English, but it is normal in Japanese. Japanese often builds the sentence by giving:

1. purpose/reason
2. time
3. degree/manner
4. main action

It is mainly talking about a habit based on a personal decision.

That is exactly why ～ことにしている is used. It combines both ideas:

• decision: the speaker chose this
• habit/rule: the speaker keeps doing it regularly

So this sentence is stronger than just saying I exercise every morning. It suggests: I intentionally keep up this routine for my health.